: I think we could get the Eternal X and Phoenix authors to release updates, and maybe we can fix Rubicon X with a plugin?

I don't see why we can't do the reverse of the Classic Limits plugin. You'd also want that plugin when playing Kill Them All, but there is a lot more content tuned for the classic limits than the expanded ones. Most of the solo maps and scenarios tagged "Aleph One" on Fileball are just conversions.

Paths is obviously the most important setting. Restoring the projectile limit could be a double-edged sword: it could keep solo battles from getting out of hand, but might also dampen multiplayer. I don't think the others affect gameplay much: collision and render limits are only noticeable when you hit them and things start going wrong.